* Posts by DB_lanky

8 posts • joined 27 Sep 2010

ANU boffins demo 'tractor beam' in water


I was wondering along the same lines, in particular how much this relies on the standing waves that are formed due to the tank shape, maybe you could use multiple generators. Should probably hunt down their paper on it...

Powershell terminal sucks. Is there a better choice?


Powershell ISE for writing scripts definitely. For day-to-day terminal based mucking around a useful free tool is ConEmu for tabbing all manner of shells, be it cygwin/powershell/cmd. It also has a full-screen/split-screen options which I find useful.


Hold our tiny silicon spheres, say gravity wave detection scientists


Re: They will never find them.

Then we'll detect the ones that happened yesterday then in that case

Dwarf galaxy yields up middle-sized black hole


What do you mean by "size"? Black holes are a technically a singularity point, so size isn't really definable! Unless you mean the event horizon? which is about 60000km for this black hole, which is pretty small compared to both stars you mentioned. In terms of mass though this black hole weighs in ~1000 times heavier than Betelgeuse and ~500 times that of VY Canis Majoris.

Faster-than-light back with surprising CERN discovery


Re: lasers depend on relativity

It doesn't really work like that, the Maxwell equations are invariant under a Lorentz transformation, which means in different moving frames of reference they are the same, or you can also say that the speed of light is constant in any frame. This doesn't necessarily mean that a working laser proves that special relativity is correct just because light is involved somewhere. You can show how a laser works without involving SR at all.

A better example of SR would be time dilation of relativistic particles http://en.wikipedia.org/wiki/Time_dilation_of_moving_particles


Re: Re: Relativity?

Nah I'm pretty sure stimulated emission (Einstein A and B coefficients) were derived from thermodynamic arguments. Lasers work due to population inversions and stimulated emission producing coherent photons, neither of which has much to do with special relativity (Though if you can prove me wrong I'd be interested to read about it!)

Also Destroy All Monsters there is QM that doesn't depend on special relativity, the Dirac equation is good for explaining spin-1/2 particles travelling at relativistic speeds, if they're going slow you don't need to use it.

Gravity wave detector gets more sensitive

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Shameless plug

Good to see the reg talking about gravitational waves! I'm a PhD student at University of Birmingham working in the field, check out our page http://gwoptics.org. We're slowly building up a simple ebook on it and a bunch of applet for people to play with and get a better understanding of it all.

Microsoft adopts invisible mobile pitch

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Not a bad advert

As far as adverts go its not that bad, especially Microsoft ones, this is far less cringe worthy than their previous ones.


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